The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. Aspects of the invention relate to an offshore wind farm or wind park comprising two or more wind turbines. In this context, the expression offshore means any location on water, e.g., at sea, ocean or a lake, near shore or far offshore.
Offshore locations are particularly useful for wind parks, since higher wind energy yields can be obtained than on shore and there are less spatial restrictions. To build offshore wind parks, buoyant foundations can be used, such as the WindFloat® system of the US company Marine Innovation & Technology.
In offshore wind farms or wind parks, a minimum distance between the wind turbines is required to prevent that turbulence caused by a wind turbine would disturb the wind flow impinging an adjacent wind turbine. FIG. 1 shows diagrammatically the calculated wake effect of a 5 MW wind turbine with a rotor diameter of 115 meter. The distance between an upstream wind turbine and other wind turbines at its leeward side should be sufficient to keep the wind turbines outside the wake area of the upstream wind turbine, so as to avoid a fall of energy conversion efficiency and undesirable loads, which may cause accelerated deterioration of wind turbine components. FIG. 1 shows the wake area in case of an invariable wind direction. However, generally the wind direction varies. This results in an extended wake area and partial wake effects necessitating further spacing of neighboring wind turbines.
Wind turbines are generally provided with yaw systems allowing them to turn with the wind and to maintain an upwind or downwind orientation with every wind direction to maximize energy efficiency. The wake area turns with the yawing of the wind turbine. As a result, the distance between the wind turbines should be large enough in all directions.